1. Technical Field
This disclosure generally relates to a breather apparatus for venting a container and, more particularly, relates to a breather apparatus with relatively compact dimensions and improved performance and durability.
2. Description of the Related Art
Breather apparatus for venting fuel tanks are known in the art. The breather apparatus may include a check valve mounted on the top wall or top opening of the tank. The check valve may be actuated either manually or automatically when the pressure within the fuel tank reaches above or drops below predetermined threshold values. For example, as fuel vapor accumulates within the tank, the pressure may rise to above a threshold high value and the valve may be actuated to release some of the fuel vapor to the outside air for safety purpose. On the other hand, when the pressure within the tank drops below a threshold low value (usually a negative pressure), the valve may be actuated to draw outside air into the tank so that desirable pressure is maintained for proper fuel delivery.
In order to mount the valve on the fuel tank, the breather apparatus may include a valve plate with a valve seat to accommodate a valve body releasably mounted thereon. A valve gasket is provided to seal the valve body against the valve plate. However, the gasket may deteriorate or fail over time, causing fuel or air leakage around the valve plate.
Moreover, some breather apparatus include an air filter operatively connected to the valve to prevent harmful particles from entering the tank. The air filters are generally cylindrical or annular blocks of porous material dimensioned to fit into the usually compact breather apparatus. However, such air filters are generally limited in filtration capacity and are prone to clogging, frequently inspection is required maintenance to ensure its optimal performance.
Finally, some breather apparatus include a cover to protect the valve. The covers generally have a top or side opening in fluid communication with the valve to allow the air and fuel vapor to enter or exit the fuel tank. However, as the cover is exposed to natural elements, dirt, mud or debris can accumulate around the cover and block the top opening, requiring immediate service to remove the blockage.
Instead of top or side vent openings on the cover, some breather apparatus include covers without any opening. To provide fluid passageways in and out of the breather apparatus, the cover may include a sidewall that surrounds, but does not engage, a sidewall of the valve plate to cooperatively define an annular space therebetween for venting purposes. However, the relatively large annular vent opening may allow large particles to be drawn into the breather apparatus and clog the air filter, the valve, or both.